This set of Biophysics Multiple Choice Questions & Answers (MCQs) focuses on “Protein Structure”.
1. What is the number of amino acids present in a Hemoglobin molecule, if each α chain and β chain contains 141 and 146 amino acids respectively in it?
a) 428
b) 292
c) 282
d) 574
View Answer
Explanation: Hemoglobin molecule is made up of 4 polypeptide chains, 2 α chain and 2 β chain.
It is given that no. of amino acids in α chain = 141 and β chain = 146.
Thus, the total number of amino acids in Hemoglobin molecule =
2 * (no. of amino acids in α chain) + 2 * (no. of amino acids in β chain) = 2 * (141) + 2 * (146) = 574.
2. An enzyme that hydrolyses peptide bonds would affect which of the following macromolecule?
a) Nucleic acid
b) Proteins
c) Carbohydrates
d) Lipids
View Answer
Explanation: Proteins are stabilised by peptide bonds, hence an enzyme that hydrolyses peptide bonds would affect proteins by degrading them.
3. What is the process of helix uncoiling and globule unfolding of proteins are called?
a) Glycosylation
b) Denaturation
c) Renaturation
d) Alkylation
View Answer
Explanation: The process of Helix uncoiling and globule unfolding of protein is known as Denaturation of proteins whereas, Renaturation of proteins is the reverse process of Denaturation. Glycosylation and Alkylation are processes involving the addition of Carbohydrate and Alkyl Group to the protein respectively.
4. β pleated sheet structure of proteins is referred to as a pleated sheet structure because it resembles the pleated folds of drape.
a) True
b) False
View Answer
Explanation: β pleated sheet structure of proteins is referred as pleated sheet structure because it resembles the pleated folds of drape. In the β structure of proteins, all peptide chains are laid together, bound by intramolecular Hydrogen bonds.
5. Which of the bond in the following structure of dipeptide Glycylalanine represent peptide bond?
NH2 – CH2 – CO – NH – CH (CH3) – COOH
a) CH2 – CO
b) CO – NH
c) CH (CH3)
d) NH2 – CH2
View Answer
Explanation: Peptide bond is a chemical bond that is formed between carboxyl group and amino group. Peptide bonds are usually found between amino acids in proteins.
6. The bond that links various amino acids together is called as __________
a) phosphodiester bond
b) glycosidic linkage
c) peptide bond
d) ester bond
View Answer
Explanation: Peptide Bond helps in linking amino acids together which results in the formation of proteins, whereas Glycosidic Linkage, Phosphodiester bonds and Ester bonds help in linking Monosaccharides, Nucleotides and Lipid Monomers respectively.
7. Which of the following structures of protein consist of a linear polypeptide chain?
a) Tertiary
b) Primary
c) Secondary
d) Quaternary
View Answer
Explanation: Primary structures of protein consist of a linear polypeptide chain whereas, secondary, tertiary/quaternary structures of proteins have two dimensional and three dimensional arrangement of polypeptides respectively.
8. Which of the following diseases is not a result of misfolding of proteins?
a) Alzheimer’s disease
b) Parkinson’s disease
c) Celiac disease
d) Huntington’s disease
View Answer
Explanation: Alzheimer’s, Parkinson’s and Huntington’s disease are caused due to misfolding of proteins whereas, Celiac disease is caused due to Immune system inflammation.
9. Which of the following bonds does not help in stabilizing Tertiary structure of protein?
a) Ionic bond
b) Disulphide bond
c) Hydrogen Bond
d) Peptide Bond
View Answer
Explanation: The tertiary structure of a protein is stabilized by mainly Ionic, Disulphide and Hydrogen bond whereas, peptide bond helps in linking various amino acids to form proteins.
10. Glycine is an optically inactive amino acid.
a) True
b) False
View Answer
Explanation: Glycine is an optically inactive amino acid because of lack of Chiral Carbon Atom. A Chiral Carbon atom is the one attached to four different types of atoms or groups of atoms in a molecule.
11. Which of the following statements related to the Domain of a protein is False?
a) They are the structural units of protein
b) They have the ability to undergo folding
c) They are dependent on the Structure of protein
d) They are the functional units of protein
View Answer
Explanation: Domain of a protein is independent of the Structure of protein. They are the functional and structural parts of a protein that have the ability to undergo folding.
Sanfoundry Global Education & Learning Series – Biophysics.
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